The invention relates to a protective tuner cover for the tuning section of a stringed musical instrument, such as a guitar. The tuner cover is sized to enclose the instrument headstock, or a substantial portion thereof, and includes a section that encloses and protects the tuning keys and knobs of the musical instrument. When constructed as a unitary structure, the tuner cover can be slid onto the instrument headstock. When constructed from separable components, the tuning cover can be opened and closed over the headstock in a bivalve manner if hinged, or by appropriately spaced latching mechanisms if completely separable. The tuner cover can be constructed to enclose and protect one or two rows of tuning keys and knobs, depending on the type of musical instrument.